This invention relates to equipment mounting structures, and particularly to such structures including cabinets, racks, frames and the like for removably housing circuit board packages used for telecommunications purposes.
In telecommunication networks, changes are constantly occurring, both in the subscribers connected to the network and to the services provided to the various subscribers. For accommodating rapid changes, the recent practice has been to terminate subscriber communication lines, e.g., metal wires and optical fibers, on circuit board packages removably housed within equipment shelves. The shelves, in turn, are mounted on various mounting structures, referred to as racks or frames and the like, which, in turn, can be mounted within enclosed cabinets. The circuit board packages include various electrical and/or optical components for processing signals arriving at the circuit board packages, and the mounting structures provide means for housing the circuit board packages and include cables for routing signals and electrical power to, between and from the various circuit boards. Changes in the network are readily achieved by replacing various circuit board packages or changing the signal routing therebetween.
For greatest flexibility of use, design standards have been established whereby different circuit board package receiving shelves can be interchanged with one another in the same and different mounting structures located in a common telephone control office or different central offices. A problem caused is that the design standards are often so complete and detailed that desired changes in the various components of the mounting structures, arising from experience with use of the mounting structures or in the design of replacement structures, are difficult to make within the existing standards.
The present invention addresses this problem primarily in the context of providing improved components for use in existing mounting structures or, owing to advantages provided by the new components, for use in new mounting structures made according to new standards.